On 2012-02-16 13:59, Anthony Liguori wrote: > On 02/16/2012 06:50 AM, Jan Kiszka wrote: >> On 2012-02-16 13:42, Anthony Liguori wrote: >>> On 02/16/2012 05:25 AM, Jan Kiszka wrote: >>>> On 2012-02-16 00:16, Igor Mammedov wrote: >>>>> Introduce a new structure CPUS as the controller of ICC (INTERRUPT >>>>> CONTROLLER COMMUNICATIONS), and new bus "ICC" to hold APIC,instead >>>>> of sysbus. So we can support APIC hot-plug feature. >>>>> >>>>> This is repost of original patch for qemu-kvm rebased on current qemu: >>>>> http://lists.nongnu.org/archive/html/qemu-devel/2011-11/msg01478.html >>>>> All credits to Liu Ping Fan for writing it. >>>>> >>>>> V2 changes: >>>>> - cpusockets_init: cpu_sockets is not yet initialized, use cpus that >>>>> we got as input param instead for qbus_create, this makes cpus >>>>> apics visible in "info qtree" monitor command >>>>> - fix format error spotted by Jan and missed by checkpatch >>>>> - cpu_has_apic_feature: return bool instead of int >>>>> >>>> >>>> This patch surely no longer applies. And the ICC requires QOM conversion. >>> >>> Also, post-QOM, I don't think having an ICC bus makes a whole lot of sense. >>> >>> The LAPIC can be made a child of the CPU device with a bidirectional link. >> >> We do have a bus here, the IO-APICs are attached to it as well. > > > Isn't that a bus protocol that's specific to the LAPICs/IO-APICs? I don't > think > that you would logically model the CPU as part of it.
Actually, MSIs go this way as well. > > I wonder if modeling inter-lapic communication via a bus is a bit overkill > compared to what we do today (just a for() loop when needed). For sure, we can keep such loops for all those use case. But Andreas may have a different vision as he wanted to eliminate (public) first_cpu references. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
